Determining whether a wireless communication node is stationary by evaluating changes in information about peer wireless communications nodes

ABSTRACT

For supporting a switch between different service modes of some service, it is determined whether a wireless communication node is stationary by evaluating changes in information about peer wireless communication nodes detected by the wireless communication node. The result of the determination is then used as a decision criterion whether to switch the service to one of at least two modes.

FIELD OF THE INVENTION

The invention relates to the field of service mode selection.

BACKGROUND OF THE INVENTION

An example of a service, in which one of several modes may be used,would be a positioning system. The positioning system allows thedetermination of the position of a receiver of the positioning system byprocessing signals transmitted by beacons of the positioning system.This receiver may, for example, be used in a mode with reduced powerconsumption, which could also be a mode in which it is turned offcompletely, or in a fully operational mode.

There is an ever increasing number of devices using such a positioningsystem in order to determine their absolute position. Most often this isachieved by making use of a Global Navigation Satellite System (GNSS),of which the American global positioning system (GPS) and the EuropeanGalileo are but two examples. These systems enable a receiver todetermine its position by just utilizing the downlink data sent by therespective set of satellites. There are also terrestrial localizationtechniques like cell identification and time difference of arrival(TDOA) that may be used for positioning which use only beacons on theground rather than in space.

Problematic signal reception conditions in some urban environments,among other things, have led to the development of assisted GNSS(A-GNSS) technology for improving the performance of GNSS when signalquality is not optimal. A variety of approaches, which are characterizedby the use of an assistance server, is subsumed under this category. Anassistance server may have a better reception of signals and/or morecomputation power and additional information useful for positioning.

While originally the kind of devices having a GNSS receiver was limited,advances in miniaturization make it possible to use GNSS receivers inever smaller and lighter devices. One exemplary kind of device to whichthis applies is the mobile phone. The positioning capability in mobilephones is most typically enabled by the use of either external orinternal receivers. Moreover, the inherent communication capabilities ofmobile phones enable a data exchange between the receiver and anassistance server

The penetration of GNSS or A-GNSS enabled terminals is expected toincrease significantly in the coming years. In 2011 it is estimated thatapproximately 30% of the terminals sold will have an internal AGNSSreceiver. But it is not only positioning capability that is steadilyadded to mobile terminals. More and more functionality that wasoriginally restricted to stationary computer systems is now a part of anincreasing variety of mobile devices. This includes the ability to runplatform-independent software like Java®, play back multimedia files andalso connect to traditional computer systems and media with technologylike universal serial bus (USB), Bluetooth® and wireless local areanetwork (WLAN). Mobile phones, vehicle infotainment systems, personaldigital assistants (PDAs) and mobile game consoles form an increasingvariety of devices which all converge in their respective capabilitiestoward a mobile general-purpose computer. This trend towards multi-useterminals consisting of multiple processors, advanced camera and videofeatures, multiple connectivity methods as well as navigation capabilityresults in an ever increasing power consumption.

Also in the case of cellular based localization techniques, for whichthe device in question does not have to be a mobile phone in the strictsense but does have mobile communication capabilities nonetheless, suchas a wrist watch with emergency mobile communications functionality,size and energy constraints may make it seem advantageous to have onlyintermittent connectivity to a cellular network.

Inertial sensors (or the consideration of the velocity solution, whichis of less practical relevance in this context) can be used fordetecting a motion of a device. If the inertial sensor detects that themobile device is in fact stationary, then there is no need tocontinuously recalculate the current position based on the receivedsignals. Consequently the positioning system receiver may be switchedoff or at least its power consumption decreased by reducing itsmeasurement rate or a similar measure. Moreover, a more accurateposition solution may be obtained if information on the state of motionof the receiver is available. If the receiver is known to be stationary,for example, a plurality of determined positions may be averaged.

It is to be understood that a switch between different available servicemodes may also be relevant to other types of services than positioning,and that service modes also do not necessarily relate to powerconsumption.

SUMMARY

A method is described which comprises determining whether a wirelesscommunication node is stationary by evaluating changes in informationabout peer wireless communication nodes detected by the wirelesscommunication node. The result of this determination is used as adecision criterion whether to switch a service to one of at least twomodes.

Further, an apparatus is described which comprises at least oneprocessing component that is configured to, firstly, determine whether awireless communication node associated to the apparatus is stationary byevaluating changes in information about peer wireless communicationnodes detected by the wireless communication node. Secondly, thecomponent is configured to use a result of the determination as adecision criterion whether to switch a service to one of at least twomodes.

The at least one processing component of the apparatus can beimplemented in hardware and/or software. It may comprise for instance aprocessor executing software program code for realizing the requiredfunctions. Alternatively, it could be for instance a circuit that isdesigned to realize the required functions, for instance implemented ina chipset or a chip, like an integrated circuit. The described apparatuscan be for example identical to the comprised processing component, butit may also comprise additional components. The apparatus could furtherbe for example a module provided for integration into a device, like awireless communication terminal or an accessory device for a wirelesscommunication terminal.

Also described is a device comprising the apparatus as described aboveand in addition a user interface. This device may also comprise areceiver for a positioning system. Alternatively or in addition, thisdevice may also comprise a wireless communication node.

Alternatively or yet in addition, this device may also be a mobileterminal.

Moreover, a computer program code is described, which realizes thedescribed method when executed by a processor.

Further, a computer program product is described in which such a programcode is stored in a computer readable medium. The computer programproduct could be for example a separate memory device, or a memory thatis to be integrated in an electronic device.

Moreover, an apparatus is described that comprises means for determiningwhether a wireless communication node associated to the apparatus isstationary by evaluating changes in information about peer wirelesscommunication nodes detected by the wireless communication node. Theapparatus further comprises means for using a result of thedetermination as a decision criterion whether to switch a service to oneof at least two modes.

Currently, the majority of mobile devices do not have inertial sensorsintegrated due to cost and size constraints. However, different wirelesscommunication capabilities are increasingly added to devices. Manydevices are provided with WLAN connectivity, Bluetooth® connectivity, orsome other similar connectivity. These may be used to help determinewhether the device is stationary or not without having to resort to adedicated and expensive inertial sensor. Thus features that areconventionally employed for non-positioning functionality are used formotion detection. Depending on the result of the motion detection, aservice may be switched into one of at least two different modes.

The invention thus provides low-cost and efficient means for detectingthat a device is stationary. The node could already be a part of thedevice and primarily be used for some other functionality, allowing thedetection of being stationary to be added at no additional cost in priceor space.

The obtained motion information can be used for different services anddifferent service modes.

In an exemplary embodiment, the at least two modes of the service of themethod described above may comprise a mode with higher power consumptionand a mode with lower power consumption.

The service may be for example a service provided by a receiver for apositioning system which is linked to the wireless communication node.The service may further be switched to a mode with reduced powerconsumption in case it has been determined that the wirelesscommunication node is stationary.

Also the information of which a change is exploited can be of variouskinds. The information about the peer wireless communication nodes maycomprise for instance the number of peer wireless communication nodesdetected by the wireless communication node.

If, for example, it has been determined that the number of peer wirelesscommunication nodes detected by the wireless communication node is equalin two scans, then this information may be indicative that the wirelesscommunication node is stationary. This indication is stronger, thegreater the number of detected peer wireless communication nodes is.

The information about the peer wireless communication nodes may alsocomprise for instance an identification of each detected peer wirelesscommunication node.

As a further example, if it has been determined that the identificationof all peer wireless communication nodes detected by the wirelesscommunication node is equal in two scans, then this information may alsobe indicative that the wireless communication node is stationary. Thisindication is also stronger, the greater the number of detected peerwireless communication nodes is.

In certain embodiments, this identification may comprise a machineaccess code number.

The information about the peer wireless communication nodes may alsocomprise for instance a signal strength of a signal received from eachof the detected peer wireless communication nodes by the wirelesscommunication node.

As yet another example, if it has been determined that the difference insignal strength of all or most peer wireless communication nodesdetected by the wireless communication node in two scans is less than apredetermined threshold, then this information may also be indicativethat the wireless communication node is stationary with a certainprobability. This indication is also stronger, the greater the number ofdetected peer wireless communication nodes is.

It is to be understood that different types of information about peercommunication nodes may also be considered in combination.

Determining whether the wireless communication node is stationary may,in one embodiment, comprise the following: The wireless communicationnode scans for peer wireless communication nodes to determine the numberand identifications of the detected peer wireless communication nodes.Then the number of identical peer wireless communication nodes detectedduring the scan that were also detected during a previous such scan andthe total number of peer wireless communication nodes that were detectedduring the scan is determined. The numerical proportion between thisnumber of identical peer wireless communication nodes and the totalnumber of peer wireless communication nodes is then evaluated todetermine whether the wireless communication node is stationary.

Determining whether the wireless communication node is stationary mayfurther comprise evaluating in addition a further value determined as afunction of the total number of peer wireless communication nodesdetected by the wireless communication node.

The greater the total number of detected peer wireless communicationnodes is, the more important a relative change in the identities of thedetected peer wireless communication nodes is. Also, the greater thetotal number of detected peer wireless communication nodes is, the moreimportant the proportion of detected peer wireless communication nodeswith significant change in their signal strength is. In order tosimplify calculations, the possible numbers of detected peer wirelesscommunication nodes may be grouped, each group being associated to arespective importance factor. To this end, for instance a look-up tablecould be employed.

Determining whether the wireless communication node is stationary mayresult for instance in a determination that either a location change ofthe wireless communication node occurred, or no location change of thewireless communication node occurred, or it is unsure whether a locationchange of the wireless communication node occurred.

For example, this determination may be made according to a numericalvalue that is indicative of the probability of a motion of a wirelesscommunication node and that is obtained based on the availableinformation about peer wireless communication nodes. If this value isabove a first threshold, then it may be determined that the wirelesscommunication node is not stationary. If this value is below a secondthreshold, which in this case would be lower than the first threshold,then it may be determined that the wireless communication node isstationary. If, on the other hand, this value is between the twothreshold values, then it may be determined that it is unsure whetherthe wireless communication node is stationary or not.

The invention can be used for example for service modes of a positioningsystem service. The positioning system can be in particular, though notexclusively, a GNSS, like GPS, global navigation satellite system(GLONASS), satellite based augmentation system (SEAS), quasi-zenithsatellite system (QZSS), local area augmentation system (LAAS) or acombination of these. LAAS makes use of pseudolites instead of truesatellites, but these pseudolites are to be understood to be covered aswell by the term satellite as used in this application. LAAS has theadvantage that it enables a positioning under indoor conditions as well.

The exploited wireless communication capabilities can be, for example,though not exclusively, short to medium range wireless communicationcapabilities, like Bluetooth® capabilities, personal area networkcapabilities, Wibree™ capabilities or WLAN capabilities. Accordingly,the employed wireless communication node could be for example either aBluetooth® wireless communication node, or a node of a personal areanetwork, or a Wibree™ wireless communication node, or a station of awireless local area network (WLAN), but also any other type of nodeenabling a wireless communication.

The invention can be employed for example in very small and lightweightelectronics applications. It can be provided for professional use, butalso for fun applications, such as a consumer entertainment electronicsdevice like a mobile phone or a mobile game console.

The service mode in question is not restriced to a mode of a positioningreceiver, nor is it restricted to relate to power consumption, nor isthe information only about motion. Any other service which mayadvantageously be switched in one or two modes depending on informationabout the environment as provided by the present invention may besubstituted for the positioning system as described for this exemplaryembodiment of the present invention.

For example, a radio tuner may search for frequencies with betterreception of specific radio stations when has been determined that theradio is not stationary. This functionality may be turned off when theradio is stationary.

As another example, a service making use of one or more sensors may beswitched from an inactive mode to an active mode upon the detection ofmotion of a wireless communication node and/or switched to an inactivemode when it has been determined that the wireless communication node isstationary. Alternatively, the service may be switched from a mode withlarger time intervals between measurements into a mode with morefrequent measurements depending on the detected presence or absence ofmotion. Such sensors may include, but are not limited to, compasses,thermometers and barometers.

Compass direction, temperature, atmospheric pressure, etc, maycontribute to an overall picture of a user's situation.

Yet another example would be a service for labeling digital data such asphotos, videos or voice records. While it is determined that a wirelesscommunication node is stationary, a mode may be selected in which allsuch digital data created in or near the node may be automaticallylabeled, for instance with location information about a last determinedor manually entered position of the wireless communication node. On theother hand, once it has been determined that the wireless communicationnode is no longer stationary, a mode may be entered in which the digitaldata is, for example, no longer labeled at all, or labeled with theindication that the location information for the digital data isunknown, or labeled with continuously updated information from apositioning receiver.

Different profiles for mobile phone operation that can be activated whenthe user of the mobile phone is, for example, in a meeting, in a car oroutdoors allow different configurations and services of the mobile phoneto be active depending on environmental conditions. To give an example,the meeting profile generally deactivates an acoustic ring tone andactivates the vibration functionality of the mobile phone. In a furtherexample, the present invention may be analogously used to automaticallyswitch to a first profile for a stationary operation and to a secondprofile for a moving operation. Different profiles may result forexample in a ring tone being played back with a different volume.

Similarly, it would also be possible to offer applications andinformation, which are only useful during motion, to a user onlywhenever a motion is detected by switching to a corresponding servicemode, and to offer applications and information, which are only usefulwhile a user is stationary, to a user only whenever no motion isdetected by switching to a corresponding service mode.

Another possible application for the present invention can be seen inthe medical field. For health reasons, persons may be recommended tomove or not move for certain times of day or for certain durations. Inthese cases, detecting that a wireless communication node carried bysuch a person is in motion according to the present invention may beused to switch a recorder into a service mode in which it is recordingin digital memory that the person is moving. Thus afterwards it may bechecked whether the actual time and duration of movement of the personduring a day, a week or another period of time corresponds to therecommended time and duration of movement during this period.

Similarly, if a wireless communication node carried for instance by anelderly person is in a mode indicating that the node is not moving for along time, then a call mode may be activated that alerts someone tocheck why the elderly person appears to be stationary.

It is to be understood that all presented exemplary embodiments may alsobe used in any suitable combination.

Other objects and features of the present invention will become apparentfrom the following detailed description considered in conjunction withthe accompanying drawings. It is to be understood, however, that thedrawings are designed solely for purposes of illustration and not as adefinition of the limits of the invention, for which reference should bemade to the appended claims. It should be further understood that thedrawings are not drawn to scale and that they are merely intended toconceptually illustrate the structures and procedures described herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram schematically illustrating a system in which anembodiment of the invention may be implemented;

FIG. 2 is a schematic block diagram of an apparatus in the system ofFIG. 1;

FIG. 3 is a diagram schematically illustrating an environment of theapparatus of the system of FIG. 1 during a first radio scan;

FIG. 4 is a diagram schematically illustrating an environment of theapparatus of the system of FIG. 1 during a second radio scan;

FIG. 5 is a flow chart illustrating an operation in the system of FIG. 1in accordance with an exemplary embodiment of the invention; and

FIG. 6 is a diagram from which a determination may be made whether theapparatus of the system of FIG. 1 is stationary or not based onavailable information.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary system, in which a selection of aservice mode based on information on wireless communication nodes can beimplemented.

The system comprises an arrangement 103 including an apparatus 100, aGNSS receiver 101 and a wireless communication node 102. The systemfurther comprises beacons 104 and various peer wireless communicationnodes 105, 106, 107, 108.

The apparatus 100 of arrangement 103 comprises processing meansconfigured to implement various algorithms. The processing means may forexample be a microcontroller unit, a miniature computer, a dedicatedintegrated circuit implemented on a chip or a signal processor. Theapparatus 100 is connected to receiver 101, which is configured toreceive positioning signals from beacons 104. The beacons 104 may besatellites, terrestrial beacons or a combination of both. The receiver101 may be for instance a receiver for a Global Navigation SatelliteSystem, like GPS, Galileo or GLONASS, or for a terrestrial navigationsystem based on GSM localization techniques like cell identification andtime difference of arrival (TDOA.

Only by way of example, it will be assumed in the following that thebeacon 104 is a GPS satellite and that the receiver 101 is a GPSreceiver.

The apparatus 100 may switch this receiver 101 in a mode with reducedpower consumption. This can mean turning the receiver 101 offcompletely, or reducing its measurement rate, or if it is based on amicroprocessor, switching it into sleep mode. The apparatus 100 may alsoswitch the receiver 101 back into fully operational mode. Generally, butnot necessarily, the apparatus 100 may also receive positioninginformation from the receiver 101. This may be the raw measured datafrom the receiver 101 or it may be already processed and determinedposition information. Thus, the actual processing of the positioningdata may occur in the receiver 101 or in the apparatus 100.

The apparatus 100 is further connected to wireless communication node102. This wireless communication node 102 may be based on any of a widevariety of wireless communication protocols. A list of examples, whichis by no means exhaustive, includes Bluetooth® or Wireless Local AreaNetwork (WLAN), like Wi-Fi®, Wibree™ or ZigBee®.

The arrangement 103 may be constituted by having apparatus 100, thereceiver 101 and the wireless communication node 102 as separate butphysically connected units or even devices connected by wires.Alternatively, any two of them may be combined in a device electricallyconnected to the distinct respective third component. In a furtherembodiment of the invention all three of the components apparatus 100,receiver 101 and wireless communication node 102 may be comprised in asingle integrated device, which would then form arrangement 103.

As an example, arrangement 103 may be or comprise a mobile device,possibly a mobile phone, an electronic wrist watch, an mp3 player, or asimilar device, either with an internal receiver 101 for a positioningsystem or a connection to an external such receiver 101 and furthereither comprising an internal wireless communication node 102 orelectrically connected to an external such wireless communication node102.

For example, the arrangement 103 may comprise a mobile phone withBluetooth® functionality, i.e. a Bluetooth® device. Another examplewould be a mobile phone with Wibree™ functionality. As another example,the mobile phone may also have ZigBee® functionality. Yet anotherexample could be a laptop computer that is also a WLAN station or alaptop computer with either an internal Bluetooth® device or connectedto an external Bluetooth® device via a universal serial bus (USB), forexample. This external Bluetooth® device may be a mobile phone with aninternal GPS receiver 101. The arrangement 103 would thus comprise anapparatus 100, the laptop computer, electrically connected to a devicecomprising both the Bluetooth® wireless communication node 102, fromwhich it may receive information, and the GPS receiver 101.

Only by way of example, it will be assumed in the following that thewireless communication nodes 102, 105-108 are Bluetooth® nodes.

The different wireless communication protocols differ widely in the kindof connections that they allow (point-to-point, point-to-multipoint) andhow control over channels is arbitrated. Generally speaking, however,each node of the wireless communication protocol in question can detectand identify peer nodes 105-108 of the same protocol that are locatedwithin the respective range of the protocol. In addition, each node isable to perform some measurements on signals emitted by peer nodes byscanning and thus without being necessarily connected to these peernodes, such as determining the respective signal strength of peer nodesthat are within the range of the protocol.

FIG. 2 illustrates a more detailed exemplary view of the apparatus 100.In this example, apparatus 100 is a microcontroller unit with a generalpurpose processor 200 running program code that implements thefunctionality of an embodiment of the present invention. The processormay also run program code for a wide variety of other functionalitiesconcurrently, for example in separate threads or processes. Theprocessor 200 has access to an interface 201 that may be used forswitching the receiver 101 into a reduced power mode and also forswitching it back to a fully operational mode. The processor 200 furtherhas access to a data interface 202 to the receiver receiving positioningsignals. The processor 200 may use information from the receiver 101 todetermine its global position, for example by making GPS positioncalculations based on GPS data received from GPS receiver 101. Theprocessor 200 also has access to a data interface 203 to the wirelesscommunication node 102. The processor 200 may receive information aboutsignals and peer wireless communication nodes 105-108 from wirelesscommunication node 102 via this data interface 203.

The processor 200 also has access to data memory 205. This memory 205may comprise random access memory (RAM) as well as read only memory(ROM). Three types of data that are relevant for the present inventionare saved in this exemplary embodiment memory 205. Firstly, there is theprogram code 206 for the positioning system. This program code 206implements all algorithms and procedures for processing the datareceived from the data interface 202 to the positioning system receiver101. Secondly, there is the program code 207 for motion detection, whichimplements the functionality for determining whether or not the wirelesscommunication node 102 interfaced by the data interface 203 isstationary or not and the functionality for causing a switch betweendifferent power modes of the GNSS receiver 103. Thirdly, there is thedata storage portion 208 used for saving data generated by the programcode 206 for the positioning system and generated by the program code207 for motion detection.

FIG. 3 illustrates the mobile apparatus 100 connected to the wirelesscommunication node 102 as described above during a first radio scan ofthe wireless network environment by wireless communication node 102. Atthis time, there are present within the range of the wirelesscommunication node 102 with MAC number 2473 a first peer wirelesscommunication nodes 302 with MAC number 3215, a second peer wirelesscommunication node 303 with MAC number 2474, a third peer wirelesscommunication node 304 with MAC number 1395, a fourth peer wirelesscommunication node 305 with MAC number 5690, and a fifth peer wirelesscommunication node 306 with MAC number 8073.

Each wireless communication node, thus also in particular the wirelesscommunication node 102 connected to the mobile apparatus 100, regularlyand periodically scans the environment for peer wireless communicationnodes. This radio scan can take place without establishing an actualconnection to the peer wireless communication nodes in question, sinceit is a necessary precondition for doing so. In the wirelesscommunication protocol, each wireless communication node is endowed withan identifier that is at least locally unique. That is, no two detectedpeer wireless communication nodes have the same identifier. In thisparticular embodiment of the present invention, this locally uniqueidentifier may be the machine access code (MAC). The machine access codedata communication sub-layer provides addressing and channel accesscontrol mechanisms that make it possible for all nodes to communicatewithin their respective network. It is a part of the data link layer orlayer 2 of the seven-layer OSI model. The individual nodes may also beidentified by other information if it is available. Thus, at any pointin time, the wireless communication node 102 has information about howmany and which peer wireless communication nodes are within the rangedetermined by the respective wireless communication protocol. In FIG. 3,this is illustrated by the machine access code number given for thewireless communication node 102 and the peer wireless communicationnodes 302-306.

In addition, generally the strength of the signal received from eachpeer wireless communication node is also determined at the wirelesscommunication node 102. By regularly performing the radio scan, temporalvariations in the strength of the signal received by each peer wirelesscommunication node may be ascertained. The totality of informationavailable about the peer wireless communication nodes is denoted radiofingerprint.

Some of these wireless communication nodes may be an integrated part ofdevices, which in turn may form a personal area network, which is acomputer network used for communication among computer devices(including telephones and personal digital assistants) close to oneperson or to one particular device. A group of wireless communicationnodes, for example Bluetooth® nodes, may form a piconet™, which is anad-hoc computer network of all the other peer devices that are withinrange of each other. These networks may be formed automatically when twoor more peer wireless communication nodes are in sufficient proximityand may be dissolved again when the respective wireless communicationnodes are outside the range of the wireless communication protocol.Likewise, individual wireless communication nodes may join or leave sucha network at any time.

FIG. 4 illustrates mobile apparatus 100 connected to wirelesscommunication node 102 during a second radio scan of the wirelessnetwork environment, i.e. at a time later than the radio scanillustrated by FIG. 3. The apparatus 100 and the wireless communicationnode 102 are identical to the mobile apparatus 100 and the wirelesscommunication node 102, respectively, from FIG. 3. At this point intime, there are present within the range of the wireless communicationnode 102 a first peer wireless communication nodes 302 with MAC number3215, a second peer wireless communication node 303 with MAC number, athird peer wireless communication node 304 with MAC number 1395, and afourth peer wireless communication node 404, with MAC number 7791.

Based on these MAC numbers, it can be established that the first peerwireless communication node 302 of FIG. 4 is identical to the first peerwireless communication node 302 of FIG. 3, and that the second peerwireless communication node 303 of FIG. 4 is identical to the secondpeer wireless communication node 303 of FIG. 3. Also the fourth peerwireless communication node 304 of FIG. 4 is identical to the third peerwireless communication node 304 of FIG. 3.

The third peer wireless communication node 404 of FIG. 4 was notdetected during the first radio scan. Likewise, the fourth peer wirelesscommunication node 305 and the fifth peer wireless communication node306 of FIG. 3 were not detected during the most recent radio scan. Thus,it may be concluded that during the second radio scan four peer wirelesscommunication nodes were detected, of which three were already detectedduring the first radio scan as well.

Based on the information about wireless communication node 102's peersand the history of change of this information, i.e. the radiofingerprint and the history of its change, it may be probabilisticallyconcluded whether or not the wireless communication node is stationary.The information about wireless communication node 102's peers and thehistory may also turn out to be inconclusive on whether or not thewireless communication node is stationary. Because wirelesscommunication node 102 is physically connected to apparatus 100, thesame result determining whether or not wireless communication node 102is stationary may also be applied to apparatus 100. Thus in thefollowing an observation of motion, an observation of no motion or anundecided result applies equally to both the wireless communication node102 and apparatus 100 in all cases.

The radio fingerprint in any one of most places is widely constant orstable. When a wireless communication node or, by the same token, theapparatus connected to it moves, the radio fingerprint changes.Consequently, a significant change in the current radio fingerprintcompared to the radio fingerprint of an earlier point in time can beused to detect movement of the wireless communication node. This islargely independent of the actual underlying wireless communicationprotocol. The greater the detected change is in the radio fingerprint,the higher the probability is for the wireless communication node notbeing stationary.

This change in the radio fingerprint manifests itself primarily, but notexclusively, in three ways. Firstly, the number of peer wirelesscommunication nodes detected during a radio scan may change relative toa previous radio scan. Secondly, the identity of the detected peerwireless communication nodes relative to a previous radio scan maychange, resulting in other peer wireless communication nodes beingdetected. And thirdly the strength of the signal received from anindividual peer wireless communication node may change relative to aprevious radio scan.

Detecting the presence or absence of motion allows saving energy onpowering the GPS receiver 101. The GPS receiver 101 may be turned off orswitched into a mode with lower power consumption, for example byreducing the measurement rate, when it has been concluded that theapparatus 100 is stationary. It may then be switched to fullyoperational mode again when it is detected that the apparatus 100 is notstationary anymore or after a predetermined time interval.

Also, detecting that the apparatus 100 is stationary for a certainperiod can be used for obtaining an accuracy gain in a positioning,since it allows averaging different positions that are obtained duringthis period.

Furthermore, if it was determined that the apparatus 100 was notstationary for a certain period of time, this period of time may be usedto estimate a maximum distance of the current position from the lastknown position before the apparatus 100 was not stationary. For example,multiplying this period of time with an assumed maximum speed of theapparatus 100 yields a radius around the last known position withinwhich the current position of the apparatus 100 can be estimated to lie.

FIG. 5 is an exemplary flow chart that describes a quantitative processwith which it may be determined whether the wireless communication node102 is stationary or not. The example takes Bluetooth® as the underlyingwireless communication protocol. However any other wirelesscommunication protocol that allows the detection and identification ofpeers within a given range may be used in an analogous and oftenidentical way. Because this process may be used continuously, theprocess is presented as a looped process that takes place concurrentlyin the processor 200 and in the wireless communication node 102.

The loop of the wireless communication node 102 comprises a first step500 and a second step 501. In the first step 500, a radio scan for peerwireless communication nodes takes place. In the second step 501, basedon the radio scan of the first step 500, peer wireless communicationnodes are detected and identified. In addition, the signal strength ofthe signal from each of the detected peer wireless communication nodesmay be determined. This process is then repeated.

The processor 200, operating concurrently, receives the number andidentity of the currently detected peer wireless communication nodes ina first step 502 from the wireless communication node 102. In addition,the processor 200 could receive the determined signal strength for eachof the detected peer wireless communication nodes from the wirelesscommunication node 102. The now following is a list of exemplary machineaccess code numbers of peer wireless communication nodes detected duringthis most recent radio scan:

000780005738000fb399aba20020e0746006000780800ed30010c6618de6000eed9d68bc000eed9d6b14000eed9d68a10020e04b21be

In a second step 503, the processor 200 determines the number andidentity of peer wireless communication nodes detected during a previousscan. This is done by reading the previously saved information about theprevious scan from the memory 205. The information comprises, in thisexample, the list of machine access code numbers of the peer wirelesscommunication nodes detected during this previous scan.

The following is the list of exemplary machine access code numbersdetected during the previous scan and read from the memory 205:

0020e04b21be000eed9d68a1000780005738000eed9d6b14000eed9d68bc0020e07460060010c6618de60012d2275e5d

In a third step 505, the processor 200 determines a location changeindex based on the information from a most recent radio scan and on theinformation from a previous scan. The radio scan immediately precedingthe most recent radio scan suggests itself to be used as the previousscan, but another one before that may also be used.

The location change index ranges from 0, which means that it is mostprobable that the wireless communication node 102, and hence theapparatus 100 and the receiver 101 connected to it, are not stationary,to 1, which means that most probably the wireless communication node102, and consequently also the apparatus 100 and the receiver 101connected to it, are stationary.

If the wireless communication node 102 detected no peer wirelesscommunication node during the most recent radio scan, the locationchange index is set to 0.5 without further proceedings until the nextradio scan. It follows that for this point in time the method produced aresult that is inconclusive on whether wireless communication node 102and apparatus 100 connected to it are stationary or not. If any peerwireless communication node has been detected during the most recentradio scan, the location change index is determined by two parameters.

The first parameter of these two is an environmental change index ECI.The environmental change index is calculated by a division, wherein thedividend is given by the number of identical peer wireless communicationnodes that were detected in the most recent scan and in the previousscan, multiplied by 100. The divisor is given by the total number ofpeer wireless communication nodes detected in the most recent scan. Thusthe equation is given as follows:

${{ECI} = {\frac{IDs}{TOTs} \cdot 100}},$

wherein IDs is the number of identical peer wireless communication nodesthat were detected in the most recent scan and in the previous scan, andwherein TOTs is the total number of peer wireless communication nodesdetected in the most recent scan. The environmental change indexessentially provides the percentage of peer wireless communication nodesthat has stayed identical from the previous radio scan to the mostrecent one.

In the Bluetooth® protocol, the locally unique identifier of the datalink layer is the machine access code number, and each wirelesscommunication protocol should have such or an equivalent number for atleast locally unique identification. By comparing the list of machineaccess code numbers of detected peer wireless communication nodes fromthe most recent radio scan with the list of machine access code numbersof detected peer wireless communication nodes from a previous scan, thenumber of identical peer wireless communication nodes can be determined.

The machine access code (MAC address) is the machine access code numberof the Ethernet protocol. In cases where the internet protocol (IP) isused over an underlying protocol that is not Ethernet, an analogousexisting identification number of the underlying protocol is ofteninterpreted as being the MAC address for the purposes of the internetprotocol. In a situation where internet protocol is used over a wirelessnetwork, this equivalent MAC address may thus be interpreted as themachine access code number for the purpose of wireless communicationnode identification in the context of the present invention as well.

As an illustrative example, the following is again the list of peerwireless communication nodes detected during the most recent radio scan,where additionally the peer wireless communication nodes that were alsodetected during the previous radio scan are denoted by an (x).

000780005738 (x)000fb399aba20020e0746006 (x)000780800ed30010c6618de6 (x)000eed9d68bc (x)000eed9d6b14 (x)000eed9d68a1 (x)0020e04b21be (x)

The most recent radio scan detected 9 peer wireless communication nodes,of which 7 are identical to the peer wireless communication nodesdetected during a previous radio scan. In this case then, theenvironmental change index is given by

${ECI} = {{\frac{IDs}{TOTs} \cdot 100} = {{\frac{7}{9} \cdot 100} \approx 77.78}}$

If the wireless communication node 102 determines as well the signalstrength of signals from peer wireless communication nodes and providesthe results to the processor 200, the processor 200 may further reducethe number of identical peer wireless communication nodes IDs by thoseidentical peer wireless communication nodes for which the detectedsignal strength varies significantly from one scan to the next.

Alternatively, an equation for IDs may be used that takes into accountsignificant changes in the signal strength of peer wirelesscommunication node that are identical to peer wireless communicationnodes detected during a previous scan. In this alternative case IDs isgiven by

${IDs} = {N_{Seq} + {N_{Sch} \cdot \frac{1}{2}}}$

where N_(Seq) is the number of identical peer wireless communicationnodes that are identical to peer wireless communication nodes detectedduring a previous scan with no significant change in signal strengthbetween the two scans and N_(Sch) is the number of identical peerwireless communication nodes that are identical to peer wirelesscommunication nodes detected during a previous scan with significantchange in signal strength between the two scans. This is only anexemplary method of taking this signal strength change into account andothers are possible.

The second parameter by which the location change index is determined isthe environmental change importance factor. The environmental changeimportance factor is determined as a function of the total number ofpeer wireless communication nodes detected during the most recent radioscan and can be implemented as simple look-up table, as given by thefollowing example:

Number of peer wireless environmental change communication nodesimportance factor 0 or 1 0 2 1 3 2 . . . . . . 10  9 >10  10 

The more peer wireless communication nodes are detected, the moresignificant a relative change in the number of identical peer wirelesscommunication nodes from the previous radio scan to the most recent onebecomes. If there is only a single peer wireless communication node itmay be one of a mobile phone of another person. The scanning node 102may be stationary, and the other person may move away, resulting in achange in the radio fingerprint even though the node 102 is in factstationary. On the other hand, the other person may also be movingtogether with the scanning node 102, thus indicating no change in theradio fingerprint even though the node 102 is in fact not stationary.With a large number of peer wireless communication nodes detected by theradio scan, it is more likely that a change in the radio fingerprintdoes indicate that the apparatus 100 and the receiver 101 connected tothe node 102 are not stationary.

The environmental change index and the environmental change importancefactor together determine the location change index. The location changeindex may for example be given by a set of curves, described byfunctions of the environmental change index, where the appropriate curveor function is determined by the environmental change importance factor.In general, for higher values of the environmental change importancefactor, the derivative of the function for the location change indexwith respect to the environmental change index will be higher as well.

Thresholds may be determined such that if the location change indexexceeds one threshold, it is determined that the wireless communicationnode 102 is not stationary. If the location change index goes belowanother threshold, it is determined that the wireless communication node102 is stationary. If the location change index neither exceeds thefirst threshold nor goes below the second threshold, then no conclusivedetermination can be made.

FIG. 6 shows an exemplary set of curves, according to which the locationchange index bt_dloc may be determined based on the environmental changeindex bt_eci and the environmental change importance factor bt_if. Fromthe location change index it follows whether the wireless communicationnode 102 is stationary or not, or whether the location change indexallows no conclusion in this question.

In FIG. 6, the threshold above which the location change index indicatesthat a location change has occurred has been exemplarily set to 0.75.The threshold below which the location change index indicates that alocation change has not occurred has been exemplarily set to 0.25. Inthis particular example, if the location change index is between 0.25and 0.75, no conclusion may be drawn about whether or not the wirelesscommunication node 102 is stationary. The relative amount of change ofthe wireless network environment is represented by the environmentalchange index. The value of the environmental change index necessary tomake such a determination varies with the importance factor which is afunction of the number of peer wireless communication nodes detectedduring the radio scan. In this particular example, an importance factorof 2 will not provide a conclusive determination no matter what theenvironmental change index is. On the other hand, for an importancefactor of 10 any environmental change index below 0.33 or above 0.66will result in a determination on whether or not the wirelesscommunication node 102 is stationary, according to this example.

In a fourth step 506, after the location change index has beencalculated in the third step 505, the processor 200 compares thecalculated location change index with the threshold for determiningwhether a location change has occurred. If from the calculated locationchange index it can be determined that a location change has occurred,it follows as an operation 507 on the positioning system receiver 101that the positioning system receiver 101 is switched into fullyoperational mode.

If none of a predetermined number of consecutive iterations has resultedin the determination that a location change has occurred, then thepositioning system receiver 101 may be switched into fully operationalmode without such a determination being made based on the locationchange index. This is to verify by means of the positioning systemreceiver 101 that in the period of time corresponding to thepredetermined number of iterations no location change has indeedoccurred. If after this verification it is still not determined that alocation change has occurred, the receiver 101 may be switched back intoa mode with reduced power consumption.

If it has been determined that a location change has occurred, theprocessor 200 then proceeds to the final step 510 of this iteration, inwhich the information about the most recent radio scan is saved in thememory 205. The same process may then be repeated for the next point intime by starting again with the first step 502.

If it has not been determined that a location change has occurred, theprocessor 200 compares the calculated location change index with thethreshold for determining that a location change has not occurred in afifth step 508. If from the calculated location change index it can bedetermined that a location change has not occurred, it follows as anoperation 509 on the positioning system receiver 101 that thepositioning system receiver 101 is switched into a mode with reducedpower consumption.

If neither a determination was made in the fourth step 506 that alocation change has occurred, nor a determination was made in the fifthstep 508 that no location change has occurred, it follows that generallythe positioning system receiver 101 remains in the state that it is in,unless the elapse of a predetermined number of iterations as describedfor the fourth step 506 results in the positioning system receiver 101to be switched into fully operational mode or unless the positioningsystem receiver 101 is switched by a process outside this presentlydescribed process for motion detection.

The processor 200 then proceeds in any case to the final step 510 ofthis iteration, in which the information about the most recent radioscan is saved in the memory 205 and a new iteration may be startedbeginning at the first step 502.

The information whether or not the apparatus is stationary may also beused for a wide variety of other applications, of which contextawareness is but one example. Thus the information that the apparatus isstationary or not may be used to supplement a part of a morecomprehensive set of information about the environment of the apparatus.Combined with other detection means, for example for optical signals,acoustic signals, or tactile signals, the motion detection functionalityof the present invention may be used to help make a determination amongdifferent scenarios consistent with the information received from otherdetection means.

Moreover, the intermediate parameters environmental change index andimportance factor may also supply information indicative of more generalinformation about the environment of the apparatus. For example, in thewilderness or in rural areas, not many Bluetooth® devices, WLAN accesspoints and the like are to be expected. On the other hand, these kindsof devices tend to concentrate within office buildings or in crowdedurban areas near buildings. Thus these parameters may support thedetermination of the general kind of environment that the apparatus isin.

It is to be understood that the same or a similar detection of alocation change could equally be used for controlling the power modes ofother components than a positioning system receiver. Further, it couldequally be used for switching between other modes than power modes ofany component.

The functions illustrated by the processor 200 executing program code207 can be viewed as means for determining whether a wirelesscommunication node is stationary by evaluating changes in informationabout peer wireless communication nodes detected by the wirelesscommunication node and as means for using a result of the determinationas a decision criterion whether to switch a service to one of at leasttwo modes.

The program code 207 can also be viewed as comprising such means in theform of functional modules.

While there have been shown and described and pointed out fundamentalnovel features of the invention as applied to preferred embodimentsthereof, it will be understood that various omissions and substitutionsand changes in the form and details of the devices and methods describedmay be made by those skilled in the art without departing from thespirit of the invention. For example, it is expressly intended that allcombinations of those elements and/or method steps which performsubstantially the same function in substantially the same way to achievethe same results are within the scope of the invention. Moreover, itshould be recognized that structures and/or elements and/or method stepsshown and/or described in connection with any disclosed form orembodiment of the invention may be incorporated in any other disclosedor described or suggested form or embodiment as a general matter ofdesign choice. It is the intention, therefore, to be limited only asindicated by the scope of the claims appended hereto. Furthermore, inthe claims means-plus-function clauses are intended to cover thestructures described herein as performing the recited function and notonly structural equivalents, but also equivalent structures.

1. A method comprising: determining whether a wireless communicationnode is stationary by evaluating changes in information about peerwireless communication nodes detected by the wireless communicationnode; and using a result of the determination as a decision criterionwhether to switch a service to one of at least two modes.
 2. The methodaccording to claim 1 wherein the at least two modes of the servicecomprise a mode with higher power consumption and a mode with lowerpower consumption.
 3. The method according to claim 1, wherein theservice is a service provided by a receiver for a positioning systemwhich is linked to the wireless communication node, and wherein theservice is switched to a mode with reduced power consumption in case ithas been determined that the wireless communication node is stationary.4. (canceled)
 5. (canceled)
 6. (canceled)
 7. The method according toclaim 1, wherein determining whether the wireless communication node isstationary comprises: scanning for peer wireless communication nodes bythe wireless communication node to determine the number andidentifications of detected peer wireless communication nodes; anddetermining the number of identical peer wireless communication nodesdetected by the wireless communication node that were also detected bythe wireless communication node during a previous scanning and the totalnumber of peer wireless communication nodes detected by the wirelesscommunication node; and evaluating a numerical proportion between thenumber of identical peer wireless communication nodes detected by thewireless communication node that were also detected by the wirelesscommunication node during a previous scanning and the total number ofpeer wireless communication nodes detected by the wireless communicationnode to determine whether the wireless communication node is stationary.8. The method according to claim 7, wherein determining whether thewireless communication node is stationary comprises evaluating inaddition a further value determined as a function of the total number ofpeer wireless communication nodes detected by the wireless communicationnode.
 9. The method according to claim 1, wherein determining whetherthe wireless communication node is stationary results in a determinationthat either a location change of the wireless communication nodeoccurred, or no location change of the wireless communication nodeoccurred, or it is unsure whether a location change of the wirelesscommunication node occurred.
 10. The method according to claim 1,wherein the service is a service provided by a global navigationsatellite system receiver.
 11. The method according to claim 1, whereinthe wireless communication node is one of: a Bluetooth® wirelesscommunication node; a node of a personal area network; a Wibree™wireless communication node; and a station of a wireless local areanetwork
 12. An apparatus comprising at least one processor and at leastone memory including computer program code, the at least one memory andthe computer program code configured to, with the at least oneprocessor, cause the apparatus at least to perform: determine whether awireless communication node associated to the apparatus is stationary byevaluating changes in information about peer wireless communicationnodes detected by the wireless communication node; and use a result ofthe determination as a decision criterion whether to switch a service toone of at least two modes.
 13. The apparatus according to claim 12,wherein the at least two modes of the service comprise a mode withhigher power consumption and a mode with lower power consumption. 14.The apparatus according to claim 12, wherein the service is a serviceprovided by a receiver for a positioning system which is linked to thewireless communication node, and wherein the at least one memory and thecomputer program code are configured to, with the at least oneprocessor, cause the apparatus to switch the service to a mode withreduced power consumption in case it has been determined that thewireless communication node is stationary.
 15. (canceled)
 16. Theapparatus according to claim 12, wherein the information about the peerwireless communication nodes comprises an identification of eachdetected peer wireless communication node.
 17. (canceled)
 18. Theapparatus according to claim 12, wherein the at least one memory and thecomputer program code are configured to, with the at least oneprocessor, cause the apparatus to determine whether a wirelesscommunication node is stationary by determining the number of identicalpeer wireless communication nodes detected by the wireless communicationnode that were also detected by the wireless communication node during aprevious scanning and the total number of peer wireless communicationnodes detected by the wireless communication node and by evaluating anumerical proportion between the number of identical peer wirelesscommunication nodes detected by the wireless communication node thatwere also detected by the wireless communication node during theprevious scanning and the total number of peer wireless communicationnodes detected by the wireless communication node to determine whetherthe wireless communication node is stationary.
 19. The apparatusaccording to claim 18, wherein the at least one memory and the computerprogram code are configured to, with the at least one processor, causethe apparatus to determine whether the wireless communication node isstationary by evaluating in addition a further value determined as afunction of the total number of peer wireless communication nodesdetected by the wireless communication node.
 20. The apparatus accordingto claim 12, wherein the at least one memory and the computer programcode are configured to, with the at least one processor, cause theapparatus to determine whether the wireless communication node isstationary comprising determining that either a location change of thewireless communication node occurred, or no location change of thewireless communication node occurred, or it is unsure whether a locationchange of the wireless communication node occurred.
 21. The apparatusaccording to claim 12, wherein the positioning system is a globalnavigation satellite system.
 22. The apparatus according to claim 12,wherein the wireless communication node is one of: a Bluetooth® wirelesscommunication node; a node of a personal area network; a Wibree™wireless communication node; and a node of a wireless local area network23. The apparatus according to claim 12 further comprising at least oneof: a user interface; a receiver for a positioning system; a globalnavigation satellite system receiver; and a wireless communication node.24. (canceled)
 25. (canceled)
 26. The apparatus according to claim 12,wherein the apparatus is a mobile terminal.
 27. (canceled)
 28. Acomputer readable medium in which a program code is stored, the programcode causing an apparatus to perform the following when executed by aprocessor: determine whether a wireless communication node is stationaryby evaluating changes in information about peer wireless communicationnodes detected by the wireless communication node; and use a result ofthe determination as a decision criterion whether to switch a service toone of at least two modes.
 29. (canceled)